Ex-boyfriend

Last year I started a relationship with my current girlfiend. Before that we had our respective partners and everything was fantastic.
She always kept in touch with her ex-boyfriend and it was not a trouble fordidn't bother me because I am not jealous at all. After a year, she said methat she is going to have an ice cream with him and it wasseemed very strange forto me because their relationship was lostover by that time (or ...their relationship was over by then).

She told me that he likes her and I could not believe thatit because they had spent too much time together (in this context in might be more natural to say "so much time together") in the past and it could be a problem for us. HopefullyThankfully, she said metold me that there is no problem with that because she loves me and I love her too. 

By chance, I met him yesterday and we were talking like friends because we had studied together at the university. He apologized to me for saying that those words to my girlfriend, but I do not trust him because the power of love is unlimited and every one is able to do everything for anybody but I said to him that I do not mind because it is a problem with my girlfriendmy girlfriend's problem. (the problem is for your girlfriend to resolve. It isn't a problem with your girlfriend - I think.)

I now know that she does not like him and I am more relaxed than yesterday. People do not should not be interacting interfering with a couple, but if you want something you must fight for it.

Good. A Lot of this reads really well and comes across quite natural. Some of the corrections are a bit pedantic, using words that are a little more natural sounding. Well done!

Ex-boyfriend

Last year I started a relationship with my current girlfriend. Before that, we had our respective partners and everything was fantastic.
She always kept in touch with her ex-boyfriend and it was not a trouble problem for me because I am not jealous at all. After a year, she said me she is going to have an ice cream with him, and it was very strange for me because their relationship was lost by the that time.

She told me that he like her and I could'nt believe it. They spent so much time together in the past, and now it could become a problem for us. She said me there is no problem with that because she loves me and I love her too.

By chance, I met him yesterday and we were talking like friends because we had studied together at the university. He apologize to me for saying that word to my girlfriend but I do not trust him, because the power of love is unlimited, and every one is able to do everything for anobody, but I said told him I don't mind, because it is a problem with my girlfriend.

I now know she dos'nt like him. I am more relaxed than I was yesterday. People do not should shouldn't be interacting interfering with a couple, but if you want something you must fight for it.